Solar Forecasting by K-Nearest Neighbors Method with Weather Classification and Physical Model

With the increasing penetration of solar photovoltaic (PV) generation in the power system, the reliability of the distribution system and efficiency of PV systems have garnered increasing attention in recent years. Forecasting the PV output is one way to decrease the uncertainty of such power systems. In this study, we present a K-Nearest Neighbors algorithm based forecasting model, which can provide the estimated PV output by utilizing numerical weather and solar irradiance prediction data. This forecasting model also includes a weather condition classification process and a physical model of PV units. Numerical results are evaluated by using data from an existing 128 kW rooftop PV system.